TW201705560A - High-frequency ultrasound piezoelectric element, manufacturing method thereof and the high-frequency ultrasound probe comprising the high-frequency ultrasound piezoelectric element - Google Patents

Abstract

The present invention relates to a manufacturing method of the high-frequency ultrasound piezoelectric element, comprising: preparing bottom electrode by coating the complex of sol-gel solution and piezoelectric powder to the bottom electrode with spray method, sintering the coated complex to form a piezoelectric film, and forming an upper electrode on the piezoelectric film. The present invention produces the high-frequency ultrasound piezoelectric element by such an easy method and also get clearer ultrasound image than the prior art.

Description

High-frequency ultrasonic piezoelectric element, method of manufacturing the same, and high-frequency ultrasonic element including the same Frequency ultrasonic probe

The present invention relates to a high-frequency ultrasonic piezoelectric element, a method of manufacturing the same, and a high-frequency ultrasonic probe including the high-frequency ultrasonic piezoelectric element, and more particularly to a high-frequency ultrasonic piezoelectric element including a piezoelectric film formed by a spray method, A manufacturing method and a high-frequency ultrasound probe including the high-frequency ultrasonic piezoelectric element.

Conventionally, an ultrasonic wave or the like is used to irradiate an ultrasonic wave inside an organism, and a reflected wave from the inside of the organism is obtained, and the obtained reflected wave is subjected to signal processing to visualize it, thereby diagnosing the properties of the organism. A piezoelectric element is used for transmission and reception of ultrasonic waves, and an oxidized piezoelectric material having a perovskite crystal structure such as lead zirconate titanate (Pb(Zr, Ti)O ₃ :PZT) is usually used as a material of the piezoelectric element. The piezoelectric element is usually produced by molding a powder made of PZT or the like into a predetermined shape such as a cube, sintering the formed body to obtain a ceramic sintered body, and then processing the sintered body as a piezoelectric film by cutting, grinding, or the like. A piezoelectric element is fabricated by mounting an electrode on the piezoelectric film in a desired shape (see, for example, Patent Document 1).

In recent years, it has been required to obtain higher definition ultrasonic images in order to obtain High-definition ultrasonic images require piezoelectric elements capable of transmitting and receiving ultrasonic waves at higher frequencies. In the case where the same material is used as the material of the piezoelectric element, it becomes possible to transmit and receive ultrasonic waves at a high frequency as the thickness of the piezoelectric film is lowered. Specifically, the driving frequency of the piezoelectric element is inversely proportional to the thickness of the piezoelectric element, and when the piezoelectric element having the piezoelectric film of 100 μm is driven at, for example, 20 MHz, the piezoelectric element made of the same material is used. When the piezoelectric film has a thickness of one-fifth of 100 μm, that is, 20 μm, the driving frequency is usually five times that of 20 MHz, that is, 100 MHz. When a piezoelectric element driven at such a high frequency of 100 MHz is used, the spatial resolution of the obtained ultrasonic image in the irradiation direction is five times that of the case where the driving frequency is 20 MHz. Therefore, in order to obtain a piezoelectric element capable of obtaining a higher definition ultrasonic image, it is necessary to form a piezoelectric film having a smaller film thickness.

Prior technical literature

Patent literature

Patent Document 1: Japanese Laid-Open Patent Publication No. H07-45124.

However, as described above, the thin film formation efficiency of the sintered body made of PZT by the machining such as cutting, grinding, etc. is low, and the thinness of the obtained film is also limited. Further, if a sintered body made of PZT having a thickness of several tens of μm to several hundreds of μm is machined, cracks or the like may occur.

The present invention has been made in view of the above problems, and an object thereof is to form a thin piezoelectric film by a simple method, and to obtain a high-frequency ultrasonic piezoelectric element capable of transmitting and receiving a high-definition ultrasonic image using the obtained piezoelectric film.

In order to achieve the above object, the present invention produces a high-frequency ultrasonic piezoelectric element by applying a composite of a sol-gel solution and a piezoelectric powder onto an electrode by a spray coating method to form a piezoelectric film.

Specifically, the method for manufacturing a high-frequency ultrasonic piezoelectric element according to the present invention includes the steps of: preparing a lower electrode; and coating a composite containing a sol-gel solution and a piezoelectric powder on the lower electrode by a spray coating method; a step of sintering the coated composite to form a piezoelectric film; and a step of forming an upper electrode on the piezoelectric film.

According to the method for producing a high-frequency ultrasonic piezoelectric element according to the present invention, a composite containing a sol-gel solution and a piezoelectric powder is applied onto the lower electrode by a spray coating method, so that the discharge amount of the composite discharged by appropriate adjustment is appropriately adjusted. The discharge time and the like can easily form a piezoelectric film having a desired film thickness in a desired region, and an extremely thin piezoelectric film of several μm can be formed.

In the method of manufacturing a high-frequency ultrasonic piezoelectric element according to the present invention, in the step of forming the upper electrode, a plurality of openings having an array shape and exposing the piezoelectric film may be disposed on the piezoelectric film. The mask covers the piezoelectric film and the mask to form the upper electrode, and then the mask is removed.

Thereby, the upper electrode is formed in an array on the piezoelectric film, and thus the obtained piezoelectric element can be applied to a so-called phased array type ultrasonic probe capable of controlling a plurality of upper electrodes. Each region of the piezoelectric film directly below emits ultrasonic waves with a specific time difference, and a cross-sectional image of the inside of the organism is obtained by electron scanning.

In this case, in the step of preparing the lower electrode, a plate-shaped lower electrode having a concave portion extending in the longitudinal direction may be prepared; in the step of forming the piezoelectric film, a piezoelectric film is formed on the bottom surface of the concave portion; In the step of the electrode, the piezoelectric film is formed along the piezoelectric film a plurality of upper electrodes arranged in the extending direction of the concave portion.

Thereby, a plurality of upper electrodes are arranged in the concave portion of the lower electrode in the extending direction of the concave portion (the longitudinal direction of the lower electrode), so that it is possible to suppress and converge the super-emission from each region of the piezoelectric film directly under the upper electrodes. The sound wave is diffused in a direction perpendicular to the extending direction of the concave portion (the width direction of the lower electrode). Therefore, when the piezoelectric element is used for an ultrasonic probe, it is not necessary to provide an acoustic lens, and the number of parts can be reduced to reduce the manufacturing cost.

In the method of manufacturing a high-frequency ultrasonic piezoelectric element according to the present invention, in the step of forming the piezoelectric film, a mask having a plurality of openings arranged in an array and exposing the lower electrode may be disposed on the lower electrode. Then, a composite body is coated on the lower electrode by a spray coating method, and the composite body is sintered to form a plurality of piezoelectric films arranged in an array.

Thereby, a plurality of thin piezoelectric films arranged in an array can be easily formed on the lower electrode. In addition, since a plurality of thin piezoelectric films can be formed in an array, the obtained piezoelectric element can be applied to a so-called phased array type ultra-probe which can control a plurality of piezoelectric films to emit each other with a specific time difference. Sound waves, using electronic scanning to obtain a cross-sectional image of the interior of the organism.

In this case, in the step of preparing the lower electrode, a plate-shaped lower electrode having a concave portion extending in the longitudinal direction may be prepared; in the step of forming the piezoelectric film, the bottom surface of the concave portion of the lower electrode is formed to be disposed along the A plurality of piezoelectric films arranged in the extending direction of the concave portion.

Thereby, the plurality of piezoelectric films are arranged on the bottom surface of the concave portion of the lower electrode in the extending direction of the concave portion (the longitudinal direction of the lower electrode), so that the ultrasonic waves emitted from the piezoelectric film can be suppressed and concentrated in the direction perpendicular to the extending direction of the concave portion. The diffusion in the direction (the width direction of the lower electrode). Therefore, when the piezoelectric element is used for an ultrasonic probe, it is not necessary to provide an acoustic lens, and the number of parts can be reduced. Reduce manufacturing costs.

In the method of manufacturing a high-frequency ultrasonic piezoelectric element according to the present invention, in the step of preparing the lower electrode, a rod-shaped lower electrode having a concave portion on the end surface may be prepared; and in the step of forming the piezoelectric film, on the bottom surface of the concave portion of the lower electrode A piezoelectric film is formed.

Thereby, since the piezoelectric film is formed on the bottom surface of the concave portion on the end surface of the rod-shaped lower electrode, it is possible to suppress and concentrate the diffusion of the ultrasonic wave emitted from the piezoelectric film from the axial direction to the outer side of the rod-shaped lower electrode. Therefore, as in the case described above, when the piezoelectric element is used for an ultrasonic probe, it is not necessary to provide an acoustic lens, and the number of components can be reduced to reduce the manufacturing cost. Further, by providing, for example, a single piezoelectric film on the end surface of the rod-shaped lower electrode, it is possible to apply to a so-called single-vibration type ultrasonic probe which can obtain a cross-sectional image of the inside of the organism by mechanical scanning, instead of the above-described phased array type ultrasonic wave. Probe.

In the method for producing a high-frequency ultrasonic piezoelectric element according to the present invention, a piezoelectric powder made of PZT can be used as the piezoelectric powder.

The high-frequency ultrasonic piezoelectric element according to the present invention is characterized in that, by the above-described manufacturing method, a lower electrode is provided, and a composite containing a sol-gel solution and a piezoelectric powder is applied onto the lower electrode by a spray method, followed by sintering. The piezoelectric film formed and the upper electrode formed on the piezoelectric film.

The high-frequency ultrasonic piezoelectric element according to the present invention includes a piezoelectric film formed by applying a composite containing a sol-gel solution and a piezoelectric powder by a spray coating method, so that the film of the piezoelectric film can be easily adjusted. Thick, it is also easy to obtain a piezoelectric film with a thin film thickness. Therefore, since the piezoelectric film having a small film thickness is provided, it is easy to obtain a high-frequency ultrasonic piezoelectric element capable of transmitting and receiving a higher-frequency ultrasonic wave.

In the high-frequency ultrasonic piezoelectric element according to the present invention, the upper electrode may be formed in plural in an array on the piezoelectric film.

Thereby, the upper electrodes are arranged in an array on the piezoelectric film, and thus the obtained piezoelectric element can be applied to a so-called phased array type ultrasonic probe which controls the piezoelectricity directly under the plurality of upper electrodes Each region of the film emits ultrasonic waves with a certain time difference from each other, and an electron scanning can be used to obtain a cross-sectional image of the inside of the organism.

In this case, the lower electrode has a plate shape and has a concave portion extending in the longitudinal direction on the surface thereof, and the piezoelectric film is formed on the bottom surface of the concave portion, and the plurality of upper electrodes are arranged on the piezoelectric film in the extending direction of the concave portion.

Thereby, a plurality of upper electrodes are arranged in the concave portion of the lower electrode in the extending direction of the concave portion (the longitudinal direction of the lower electrode), so that it is possible to suppress and converge the super-emission from each region of the piezoelectric film directly under the upper electrodes. The sound wave is diffused in a direction perpendicular to the extending direction of the concave portion (the width direction of the lower electrode). Therefore, when the piezoelectric element is used for an ultrasonic probe, it is not necessary to provide an acoustic lens, and the number of parts can be reduced to reduce the manufacturing cost.

In the high-frequency ultrasonic piezoelectric element according to the present invention, the piezoelectric film may be formed in plural in an array on the lower electrode.

Therefore, since the piezoelectric film is formed in a plurality of arrays, it can be applied to a so-called phased array type ultrasonic probe which controls a plurality of piezoelectric films to emit ultrasonic waves with a specific time difference, thereby making use of the ultrasonic film. An electronic scan obtains a cross-sectional image of the interior of the organism.

In this case, the lower electrode has a plate shape and has a concave portion extending in the longitudinal direction on the surface thereof, and a plurality of piezoelectric films are arranged in the extending direction of the concave portion and disposed on the bottom surface of the concave portion of the lower electrode.

Thereby, the plurality of piezoelectric films are arranged on the bottom surface of the concave portion of the lower electrode in the extending direction of the concave portion (the longitudinal direction of the lower electrode), so that the ultrasonic waves emitted from the piezoelectric film can be suppressed and concentrated in the direction perpendicular to the extending direction of the concave portion. The diffusion in the direction (the width direction of the lower electrode). Therefore, when the piezoelectric element is used for an ultrasonic probe, it is not necessary to provide an acoustic lens, and the number of parts can be reduced to reduce the manufacturing cost.

In the high-frequency ultrasonic piezoelectric element according to the present invention, the lower electrode has a rod shape and its end surface has a concave portion, and the piezoelectric film can be formed on the bottom surface of the concave portion.

Thereby, since the piezoelectric film is formed on the bottom surface of the concave portion on the end surface of the rod-shaped lower electrode, it is possible to suppress and concentrate the diffusion of the ultrasonic wave emitted from the piezoelectric film from the axial direction to the outer side of the rod-shaped lower electrode. Therefore, as in the case described above, when the piezoelectric element is used for an ultrasonic probe, it is not necessary to provide an acoustic lens, and the number of components can be reduced to reduce the manufacturing cost. Further, by providing, for example, a single piezoelectric film on the end surface of the rod-shaped lower electrode, it is possible to apply to a so-called single-vibration type ultrasonic probe which can obtain a cross-sectional image of the inside of the organism by mechanical scanning, instead of the above-described phased array type ultrasonic wave. Probe.

In the high-frequency ultrasonic piezoelectric element according to the present invention, the piezoelectric powder may be a piezoelectric powder made of PZT.

The high frequency ultrasonic probe according to the present invention is characterized by comprising the above-described high frequency ultrasonic piezoelectric element.

According to the high-frequency ultrasonic probe of the present invention, since the high-frequency ultrasonic piezoelectric element having the above-described effects and effects is included, a thinner piezoelectric film can be easily obtained, and a high-frequency ultrasonic wave can be transmitted and received, and as a result, a higher frequency can be obtained. High definition image.

High-frequency ultrasonic piezoelectric element according to the present invention, manufacture thereof The method and the high-frequency ultrasonic probe including the high-frequency ultrasonic piezoelectric element apply a composite containing a sol-gel solution and a piezoelectric powder on the lower electrode by a spray method, so that an extremely thin piezoelectric film can be easily obtained. As a result, a higher-frequency ultrasonic wave can be transmitted and received, and a high-frequency ultrasonic probe capable of obtaining a higher-definition image can be obtained.

10, 20, 30‧‧‧ High-frequency ultrasonic piezoelectric components

11, 21, 31‧‧‧ lower electrode

12, 22, 32‧‧‧ piezoelectric film

13‧‧‧ mask layer

14‧‧‧ openings

15, 25, 35‧‧‧ upper electrode

26, 36‧‧‧ recess

1(a) to 1(f) are cross-sectional views showing, in order, a manufacturing process of the high-frequency ultrasonic piezoelectric element according to the first embodiment of the present invention.

Fig. 2 is a plan view showing a high-frequency ultrasonic piezoelectric element according to a first embodiment of the present invention.

Fig. 3 is a cross-sectional view showing a high-frequency ultrasonic piezoelectric element according to a modification of the first embodiment of the present invention.

Fig. 4 (a) is a cross-sectional view showing a high-frequency ultrasonic piezoelectric element according to a second embodiment of the present invention, and Fig. 4 (b) is a plan view showing a high-frequency ultrasonic piezoelectric element according to a second embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail based on the drawings.

Example 1

Hereinafter, a method of manufacturing the high-frequency ultrasonic piezoelectric element 10 according to the first embodiment of the present invention and a configuration thereof will be described with reference to FIGS. 1(a) to 1(f) and FIG.

First, as shown in Fig. 1(a), a flat plate-shaped lower electrode 11 is prepared. The material of the lower electrode 11 is not particularly limited as long as it is a conductive material made of a metal which is generally used as an electrode. In addition, the thickness of the lower electrode 11 is not particularly limited, and may be appropriately selected from the viewpoint of downsizing and strength of the piezoelectric element, and is, for example, 10 μm to 150 μm.

Next, as shown in FIG. 1(b), the piezoelectric film 12 is formed on the lower electrode 11. The piezoelectric film 12 is obtained by applying a composite containing a sol-gel solution and a piezoelectric powder to the lower electrode 11 by a spray coating method by a spray coating method, and sintering the applied composite. For example, the sol-gel solution is obtained by dissolving a metal alkoxide in a solvent such as ethanol or methanol, and preferably a PZT sol-gel solution containing a lead alkoxide, a zirconium alkoxide and a titanium alkoxide. In addition, PZT can be used as the material of the piezoelectric powder. The composition ratio (weight ratio) of the sol-gel solution to the piezoelectric powder may be, for example, a sol-gel solution: piezoelectric powder = 1:1 to 2:1. Further, the piezoelectric powder preferably has a particle diameter of 50 to 1000 nm. The discharge amount of the composite, the discharge time, the distance from the discharge to the lower electrode, and the like in the spray method can be appropriately changed depending on the film thickness of the piezoelectric film to be formed or the like. In order to obtain a piezoelectric element capable of transmitting and receiving a higher-frequency ultrasonic wave, the piezoelectric film can be thinned, and if the spraying method is used, the film can be easily thinned by controlling the discharge amount or discharge time of the composite body, for example, Under the condition that the discharge time is 200 ms, a composite layer having a film thickness of about 10 μm can be formed. After coating by the spray coating method, the composite layer was dried at about 150 ° C for 5 minutes, temporarily sintered at about 450 ° C for 5 minutes, and fired at about 650 ° C for 5 minutes, and then, for example, by electricity. The corona discharge is subjected to polarization treatment to obtain a piezoelectric film 12.

Next, as shown in FIG. 1(c), a mask layer 13 is disposed on the piezoelectric film 12. The material of the mask layer 13 may be, for example, a material such as resin, glass, wood or paper, but is not limited thereto.

Next, as shown in FIG. 1(d), a plurality of openings 14 exposing the piezoelectric film 12 are formed on the mask layer 13. The opening portion 14 is provided at a position where the upper electrode 15 needs to be formed later, and is disposed at equal intervals along the longitudinal direction of the lower electrode in the present embodiment. The formation of the opening portion 14 may be chemically treated by an etching method or the like according to the material of the mask layer 13, or may be mechanically treated by cutting or the like. In the present embodiment, the opening portion 14 is formed after the mask layer 13 is disposed on the piezoelectric film 12, but The opening portion 14 is formed in advance on the mask layer 13 before the mask layer 13 is placed on the piezoelectric film 12, and the mask layer 13 on which the opening portion 14 is formed is placed on the piezoelectric film 12.

Next, as shown in FIG. 1(e), the upper electrode 15 is formed on the piezoelectric film 12 and the mask layer 13. The material of the upper electrode 15 is not particularly limited as long as it is a conductive material which can be generally used as an electrode. For example, a metal such as gold or silver can be used. Further, the upper electrode 15 can be formed by a conventional method such as a vapor deposition method or a sputtering method. The thickness of the upper electrode 15 is not particularly limited, and may be appropriately selected from the viewpoint of miniaturization and strength of the piezoelectric element, and is, for example, 10 μm to 150 μm.

Next, as shown in FIG. 1(f), the mask layer 13 is removed, and the upper electrode 15 remains only on the piezoelectric film 12 in the opening portion 14. Although not shown, the high-frequency ultrasonic piezoelectric element 10 of the present embodiment can be obtained by connecting the leads connected to the power source to the lower electrode 11 and the plurality of upper electrodes 15, respectively.

For the sake of convenience, FIG. 1 shows that three opening portions 14 are formed on the mask layer 13, and three upper electrodes 15 are formed. However, of course, the present invention is not limited thereto, and five upper electrodes may be formed as shown in FIG. 15, it is also possible to form more than five required numbers of upper electrodes 15. In the present embodiment, a plurality of upper electrodes 15 are formed in an array on the piezoelectric film 12. Specifically, as shown in FIG. 1(f) and FIG. 2, the upper electrodes 15 are arranged to be arranged along the length direction of the lower electrodes 11. . Thus, by using the high-frequency ultrasonic piezoelectric element 10 in which the upper electrode 15 is disposed in the ultrasonic probe for imaging the cross section inside the organism, a so-called phased array type ultrasonic probe can be obtained. The ultrasonic probe emits ultrasonic waves by applying a voltage to the upper electrode so that the respective regions of the piezoelectric film located directly under the plurality of upper electrodes emit ultrasonic waves with a specific time difference, whereby the cross-sectional image of the inside of the organism can be obtained by electronic scanning. The high-frequency ultrasonic probe including the high-frequency ultrasonic piezoelectric element of the present embodiment is similar to the conventional ultrasonic probe in the probe body from the proximal end side to the distal end side. The backing is provided with a backing material, a piezoelectric element of the present embodiment, an acoustic matching layer, and an acoustic lens (acoustic lens). However, in the high-frequency ultrasonic probe of the present embodiment, the substrate and the acoustic matching layer are not essential structures.

Further, in the present embodiment, as described above, a plurality of upper electrodes are formed on the piezoelectric film formed to cover the lower electrode by the mask having the opening, but a mask having openings formed in an array may be used. A plurality of piezoelectric films arranged in an array are formed on the lower electrode, and upper electrodes are formed on the plurality of piezoelectric films, respectively. Thereby, since a plurality of piezoelectric films are separated from each other when the piezoelectric film material is sprayed, it is not necessary to perform a cutting process of dicing the piezoelectric film in order to prevent crosstalk in the piezoelectric element. In particular, it is advantageous in that it is difficult to perform the cracking of the thin piezoelectric film due to cracking or the like.

In the present embodiment, the high-frequency ultrasonic piezoelectric element 10 is formed using the flat plate-shaped lower electrode 11. However, a plate-shaped lower electrode having a concave portion extending in the longitudinal direction on the surface may be used, and a piezoelectric film and an upper electrode may be formed in the concave portion. Thereby forming a high frequency ultrasonic piezoelectric element. A high-frequency ultrasonic piezoelectric element of this form will be described as a modification of the first embodiment with reference to FIG. 3. In the present embodiment, the description of the same points as those of the first embodiment will be omitted, and only the differences will be described in detail. In addition, FIG. 3 is a view showing an ultrasonic piezoelectric element equivalent to the high-frequency ultrasonic piezoelectric element shown in FIG. 2 except that the lower electrode has a concave portion, and particularly shows a cross section along the longitudinal direction of the upper electrode on one of the upper electrodes. That is, in the high-frequency ultrasonic piezoelectric element according to the present modification, the upper electrodes are arranged in plural in a direction perpendicular to the sheet surface of Fig. 3 .

As shown in FIG. 3, the high-frequency ultrasonic piezoelectric element 20 of the present modification includes a lower electrode 21 having a concave portion 26 formed on its surface. The recess 26 is formed to extend in the longitudinal direction of the lower electrode 21. Further, the peripheral edge portion of the opening of the recessed portion 26 (the boundary portion between the surface of the lower electrode 21 and the recessed portion 26) is chamfered (rounding). A piezoelectric film 22 is formed on the bottom surface of the concave portion 26 of the lower electrode 21. The piezoelectric film 22 is formed along the bottom surface shape of the concave portion 26. An upper electrode 25 is formed on the piezoelectric film 22. Similarly to the above-described first embodiment, the upper electrode 25 is provided in plural in the longitudinal direction of the lower electrode 21, that is, in the extending direction of the concave portion. In the high-frequency ultrasonic piezoelectric element 20 of the present modification, the piezoelectric film 22 and the upper electrode 25 can be formed in the same manner as the high-frequency ultrasonic piezoelectric element 10 of the first embodiment, except that the lower electrode 21 having the concave portion 26 is used. The method is carried out.

Further, in the present modification, a plurality of piezoelectric films arranged in the extending direction of the concave portion are formed on the lower electrode, and the upper electrode is formed on each of the plurality of piezoelectric films. As a result, as described above, since a plurality of piezoelectric films are separated from each other when the piezoelectric film material is sprayed, it is not necessary to perform processing such as cutting of the piezoelectric film in order to prevent crosstalk in the piezoelectric element.

In the high-frequency ultrasonic piezoelectric element 20 of the present modification, the surface of the lower electrode 21 is formed with the concave portion 26 extending in parallel with the arrangement direction of the piezoelectric film 22. Therefore, the piezoelectric film 22 disposed in the concave portion 26 can be suppressed and concentrated. The emitted ultrasonic waves are diffused in a direction perpendicular to the extending direction of the concave portion 26 (the width direction of the lower electrode 21). As a result, when the high-frequency ultrasonic piezoelectric element 20 is used for an ultrasonic probe, it is not necessary to provide an acoustic lens.

Example 2

Next, a high-frequency ultrasonic piezoelectric element 30 according to a second embodiment of the present invention will be described with reference to Fig. 4 . In the present embodiment, the description of the same points as those of the above-described first embodiment and a modification thereof will be omitted, and only differences will be described in detail. The high-frequency ultrasonic piezoelectric element 30 of the present embodiment is different from the high-frequency ultrasonic piezoelectric element 10 of the first embodiment in that the rod-shaped lower electrode 31 is used as the lower electrode and the single piezoelectric film 32 and the upper electrode 35 are formed. .

As shown in FIGS. 4(a) and (b), in the high-frequency ultrasonic piezoelectric element 30 of the present embodiment, The lower electrode 31 has a rod shape as described above, and is particularly cylindrical. Further, one end surface of the lower electrode 31 is formed with a spherical segment shaped recess 36 having a circular opening. The peripheral edge portion of the opening of the recessed portion 36 (the boundary portion between the surface of the lower electrode 31 and the recessed portion 36) is chamfered. For example, the lower electrode 31 has a diameter of 10 mm in cross section, the recess 36 has an opening diameter of 6 mm, and the recess 36 has a depth of 2 mm. Of course, these dimensions are only an example, and are not limited thereto, and these dimensions may be appropriately selected.

A piezoelectric film 32 is formed on the bottom surface of the concave portion 36 of the lower electrode 31. The piezoelectric film 32 is formed along the shape of the bottom surface of the recess 36. In the present embodiment, as in the first embodiment, the piezoelectric film 32 can be formed by coating and sintering of the composite by the spray coating method. An upper electrode 35 is formed on the piezoelectric film 32. The upper electrode 35 is also formed along the bottom surface of the recess 36. In the high-frequency ultrasonic piezoelectric element 30 of the present embodiment, before the upper electrode 35 is formed, a mask layer having a plurality of openings is not particularly formed, but a single film is formed on the piezoelectric film 32 by a vapor deposition method or the like. The upper electrode 35 is constructed. Further, although not shown, in the same manner as in the first embodiment, leads connected to a power source are connected to the lower electrode 31 and the upper electrode 35, respectively.

In the high-frequency ultrasonic piezoelectric element 30 of the present embodiment, the end surface of the rod-shaped lower electrode 31 is formed with the piezoelectric film 32 and the upper electrode 35, so that it can be used for a single vibrator type which is used for mechanical scanning. Ultrasonic probe. Further, the high-frequency ultrasonic probe including the high-frequency ultrasonic piezoelectric element 30 of the present embodiment can have the same configuration as that of the first embodiment. Further, in the high-frequency ultrasonic piezoelectric element 30 of the present embodiment, the piezoelectric film 32 and the upper electrode 35 are formed in the concave portion 36 formed on the end surface of the rod-shaped lower electrode 31, and thus the ultrasonic waves emitted from the piezoelectric film 32 are concentrated. It does not spread from the axial direction of the lower electrode 31 to the outside. As a result, when the high-frequency ultrasonic piezoelectric element 30 is used for an ultrasonic probe, it is not necessary to provide an acoustic lens.

As described above, the high-frequency ultrasonic piezoelectric element according to the present invention, the method of manufacturing the same, and the high-frequency ultrasonic probe including the high-frequency ultrasonic piezoelectric element are coated with a sol-gel solution and a pressure on the lower electrode by a spray coating method. Since the composite of the electric powder can easily obtain an extremely thin piezoelectric film, as a result, it is possible to transmit and receive a higher-frequency ultrasonic wave, and a high-frequency ultrasonic probe capable of obtaining a higher-definition image can be obtained.

The embodiments of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the invention.

10‧‧‧High frequency ultrasonic piezoelectric element

11‧‧‧ lower electrode

12‧‧‧Piezoelectric film

13‧‧‧ mask layer

14‧‧‧ openings

15‧‧‧Upper electrode

Claims (15)

A method for manufacturing a high-frequency ultrasonic piezoelectric element, comprising the steps of: preparing a lower electrode; applying a composite containing a sol-gel solution and a piezoelectric powder to the lower electrode by spraying; a step of sintering the coated composite body to form a piezoelectric film; and forming an upper electrode on the piezoelectric film. The method of manufacturing a high-frequency ultrasonic piezoelectric element according to claim 1, wherein in the step of forming the upper electrode, a plurality of openings having an array and exposing the piezoelectric film are disposed on the piezoelectric film. A mask covers the piezoelectric film and the mask to form an upper electrode, and then the mask is removed. The method of manufacturing a high-frequency ultrasonic piezoelectric element according to claim 2, wherein in the step of preparing the lower electrode, a plate-shaped lower electrode having a concave portion extending in a longitudinal direction is prepared; and in the step of forming the piezoelectric film, The piezoelectric film is formed on the bottom surface of the concave portion; and in the step of forming the upper electrode, a plurality of upper electrodes arranged in the extending direction of the concave portion are formed on the piezoelectric film. The method of manufacturing a high-frequency ultrasonic piezoelectric element according to claim 1, wherein in the step of forming the piezoelectric film, a plurality of openings having an array of the openings and exposing the lower electrodes are disposed on the lower electrode. The cover is then coated on the lower electrode by a spray method to form the composite, and the composite is sintered to form a plurality of piezoelectric films arranged in an array. A method of manufacturing a high frequency ultrasonic piezoelectric element according to claim 4, wherein In the step of preparing the lower electrode, a plate-shaped lower electrode having a concave portion extending in the longitudinal direction is prepared; and in the step of forming the piezoelectric film, a bottom surface of the concave portion of the lower electrode is disposed along the concave portion A plurality of piezoelectric films arranged in the extending direction. The method of manufacturing a high-frequency ultrasonic piezoelectric element according to claim 1, wherein in the step of preparing the lower electrode, a rod-shaped lower electrode having a concave portion on an end surface is prepared; and in the step of forming the piezoelectric film, the above-mentioned lower electrode The bottom surface of the recess forms a piezoelectric film. The method of producing a high-frequency ultrasonic piezoelectric element according to any one of claims 1 to 6, wherein a piezoelectric powder made of PZT is used as the piezoelectric powder. A high-frequency ultrasonic piezoelectric element characterized by a high-frequency ultrasonic piezoelectric element manufactured by the method of manufacturing a high-frequency ultrasonic piezoelectric element according to claim 1, wherein the high-frequency ultrasonic piezoelectric element comprises: a lower electrode; and the lower electrode is sprayed a piezoelectric film formed by applying a composite containing a sol-gel solution and a piezoelectric powder and then sintering, and an upper electrode formed on the piezoelectric film. The high-frequency ultrasonic piezoelectric element according to claim 8, wherein the upper electrode is formed in plural in an array on the piezoelectric film. The high-frequency ultrasonic piezoelectric element according to claim 9, wherein the lower electrode has a plate shape, and a surface thereof has a concave portion extending in a longitudinal direction; the piezoelectric film is formed on a bottom surface of the concave portion; A plurality of the upper electrodes are arranged in the extending direction of the concave portion and are disposed on the piezoelectric film. The high-frequency supersonic wave piezoelectric element according to claim 8, wherein the piezoelectric film is formed in plural in an array shape on the lower electrode. The high-frequency supersonic piezoelectric element according to claim 11, wherein the lower electrode has a plate shape, and a surface thereof has a concave portion extending in a longitudinal direction; and the plurality of piezoelectric films are arranged in the extending direction of the concave portion and disposed on the lower electrode On the bottom surface of the above recess. The high-frequency supersonic piezoelectric element according to claim 8, wherein the lower electrode has a rod shape and has an end surface having a concave portion; and the piezoelectric film is formed on a bottom surface of the concave portion. The high frequency ultrasonic piezoelectric element according to any one of claims 8 to 13, wherein the piezoelectric powder is made of PZT. A high frequency ultrasonic probe comprising the high frequency ultrasonic piezoelectric element according to any one of claims 8 to 14.